Variable resistance assembly



y 7, 1963 L. J. RAVER ETAL 3,089,111

, VARIABLE RESISTANCE ASSEMBLY Filed Dec. 7, 1959 2 Shun-Shut 1 l l I I I I I l I H4 5 l; |z

F 'g 2 Lou/s JRISTVXENTORS BY Thomas E. Kirk The'i'r Afforney 6.3 L. J. RAVER ETAL 3,089,111

VARIABLE RESISTANCE ASSEMBLY Filed Deb. 7, 1959 2 Shuts-Shut 2 INVENTORS Louis J. Raver y Thomas E. Kirk CRMML Their Affomey United States Patent 3,089,111 VARIABLE RESISTANCE ASSEMBLY Louis J. Raver and Thomas E. Kirk, Anderson, 1116., as-

signors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 7, 1959, Ser. No. 857,725 3 Claims. (Cl. 338-260) This invention relates to resistance assemblies having a plurality of taps which has particular utility in adjusting the operating characteristics of a voltage regulator of the type employed in regulating the output of a generator in a motor vehicle electrical system.

One of the objects of this invention is to provide a resistance assembly for a regulator that is small in size and economical to manufacture.

Still another object of this invention is to provide a resistance assembly for a regulator wherein the assembly is mounted against the metal base of the regulator and wherein the tap points of the resistor are selectively connected directly to the metal base by a member termed of electrically conductive material which may be shifted from one tap point to another and when in position is supported by the base.

A further object of this invention is to provide a resistance assembly for a regulator that includes an insulator that is wound with a resistance wire, there being a plurality of hollow rivets engaging the resistance wire at predetermined points to form tap points, and further wherein the resistance assembly is supported by the metal base of the regulator in such a position that the hollow rivets are located in alignment with threaded openings formed in the base, there being a threaded fastener that may be selectively passed through a rivet and threaded into the base for electrically connecting a given rivet with the base member.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a circuit diagram of a voltage regulator that employs the resistance assembly of this invention.

FIGURE 2 is a front view of a regulator having the resistance assembly oat this invention.

FIGURE 3 is a view partly in section of a portion of the regulator illustrated in FIGURE 2.

FIGURE 4 is a perspective view of a resistance assembly made in accordance with this invention.

FIGURE 5 is an end view of the resistance assembly illustrated in FIGURE 4.

Referring now to the drawings and more particularly to FIGURE 1, a voltage regulator designated in its entirety by reference numeral is illustrated which employs the resistance assembly of this invention. This regulator has a terminal 34 which is adapted to be connected to one side of the battery in a motor vehicle electrical system. and to one side of the power source which may be a DC. generator or could be an A.C. generator fitted with rectifiers. Without going into great detail the voltage regulator includes the transistors 14 and 16, a pn junction semi-conductor rectifier 18, a Zener diode 20, a second pn junction semi-conductor rectifier 22, resistors 24, 2'6 and 28 together with condensers 30 and 32. The regulator has a field terminal 12 which is adapted to be connected with the field winding of the power source which as noted hereinbefore may be of any direct current type. The voltage regulator 10 further includes a voltage dividing network including resistors 36, 38 and 40. The resistor 38 is of the potentiometer type having 3,039,111 Patented May 7, 1963 a tap point 42 connected to one side of the Zener diode 20 and with the condenser-s 30 and 32.

The voltage dividing resistors 36, 38 and 40 are connected with the resistance assembly of this invention which includes resistors 44, 46, 48 and 50. The resistor 36 is connected with resistor 44- by a conductor 52 and it is seen that various tap points 54, 56, 58 and 60 are provided which actually take the form of hollow metal rivets as will become more readily apparent hereinafter. The base of the regulator is designated in its entirety by refer ence numeral 62 and is shown in dotted lines in FIGURE 1. This base is connected to ground in a motor vehicle electrical system and is formed with threaded openings 64, '66, 68 and 70 in a manner to be more fully described hereinafter. It can be seen from the circuit diagram of FIGURE 1 that one side of the p11 junction semi-conductor rectifier 22 is connected with the base and thus to ground as is one side of the resistor 50.

The voltage regulator of FIGURE 1 operates to control the field current of the field winding that is connected with terminal 12. Thus, field current will be controlled by turning the transistor 14 on and oil and this transistor operates opposite to the conduction of transistor 16. In other words, when transistor 16 is substantially fully conductive, transistor 14 becomes substantially non-conductive and vice versa. The conduction of transistor 16 is controlled by a circuit network including the Zener diode 20 and the voltage which is sensed by this circuit network depends upon the resistance appearing between tap point 42 and ground. It will be appreciated that this resistance may be varied by selectively connecting tap points. 54, 56, 58 and 60 respectively with the openings 64, 66, 63 and 70 formed in the regulator base 62.

' Referring now more particularly to FIGURE 4, it is seen that the resistance assembly of this invention includes a sheet of insulating material 71 upon which is wound a length of resistance wire forming resistors 50, 48, 46, and 44. The resistance assembly is fabricated by first fitting the insulator board 71 with a plurality of metal hollow eyelet-s or rivets 72, 60, 58, 56 and '54. When the rivets are in place on the insulator board 71, the insulation is scraped from a portion of the wire and this portion is wrapped under the eyelet 54. The wire is then wound around the insulator 71 to form the resistor 44, is then wound under eyelet 56 and so on until resistors 44, 46, 48 and 50 are formed with the resistance wire passing around the intermediate eyelets. In each case, it is necessary to scrape the insulation ed the wire where the wire is to contact an eyelet. After the wire is wound on the insulator board and around the eyelets, the eyelets have crimping pressure applied to them so as to form a tight connection between a given eyelet and the resistance wire.

The resistance assembly illustrated in FIGURES 4 and 5 is secured to the metal base 62 of the voltage regulator 10 in a manner illustrated in FIGURES 2 and 3 of the drawings. It can be seen from FIGURE 3 that the resistance assembly illustrated in FIGURES 4 and 5 is interposed between sheets of insulating material 73 and 74. A rivet passing through the eyelet 72 in the resistance assembly serves to secure the resistance assembly and the insulators 73 and 74 to the base of the regulator 62. This rivet 75 also serves to electrically connect the hollow eyelet or rivet 72 with the base member 62 and it is thus seen that the rivet 75 serves to connect the eyelet 72 with ground potential. Rivets 76 are also provided which serve to hold the resistance assembly fixed with respect to the base 10, and do not serve any electrical function. The eyelet 54 is suitably connected with the resistor 36, which is not illustrated in FIGURES 2 and 3, by any suitable means such as a strap connector.

The flanged portion 78 of the regulator base is formed with a plurality of threaded openings 64, 66, 63 and 70, the opening 68 being illustrated in FIGURE 3. These openings 64, 66, 6S and 70 are located respectively in alignment with the hollow eyelets or rivets 54, 56, 58 and 60. When it is desired to connect a particular eyelet with the base member 62, a screw 80 is passed through one of the eyelets and is threaded into one of the threaded openings formed in the flanged portion 78 of the base 62. In FIGURE 3, the screw 80 is shown connecting the eyelet 58 with the base member, the screw being threaded into the threaded opening 68. It will be appreciated that the screw 81 may be shifted from one eyelet to another to provide a predetermined voltage adjustment for the voltage regulator 10. It thus can be seen that if it is desired to change the voltage adjustment of the regulator, it is only necessary to unscrew the fastener 80 from its position in the threaded opening 68 and then pass the screw through another eye let and into another threaded opening. This provides for simple and accurate adjustment of the voltage regulator and does not greatly increase the size of the regulator since the resistance assembly is relatively small in width and is mounted in compact relationship with the side flange 78 of the base member 62.

While the embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In combination, a metal base formed with a side flange, said side flange having a plurality of spaced threaded openings, a resistance assembly supported by said side flange including a sheet of insulating material upon which is wound a length of resistance wire, a plurality of eyelets located in spaced openings in said insulating material and connected With spaced points of said resistance wire, one of said eyelets being connected with the end of the length of said resistance Wire, said eyelets being located respectively in alignment with the threaded openings formed in said side flange, first and second sheets of insulating material one of which is positioned between said resistance assembly and said side flange and the other of which is Positioned on the opposite side of said resistance assembly, an electrically conductive rivet passing through said one eyelet and engaging said side flange for electrically connecting said one eyelet with said side flange and for mechanically supporting said resistance assembly and said sheets of insulating material from said side flange, and a screw adapted to be passed through another of said eyelets and threaded into one of said threaded openings for electrically connecting another of said eyelets with said side flange.

2. In combination, a metal base formed with a side flange, a plurality of threaded openings in said side flange, a resistance assembly formed of a thin sheet of insulating material carrying a length of resistance Wire, a plurality of metal eyelets each having a flange portion located in spaced openings formed in said insulating maerial, said eyelets being connected with spaced points of said resistance wire with portions of said resistance wire being wedged between said flange portion of the eyelet and the said insulating material at said spaced points, means for supporting said resistance assembly in such a position that said eyelets are in alignment with said threaded openings, means for insulating opposite sides of said resistance assembly including a pair of insulating sheets, means for supporting said resistance assembly from said side flange including an electrically conductive rivet which passes through one of said eyelets to electrically connect said one eyelet with said metal base memher, and a fastener formed of electrically conductive material adapted to pass through one of said eyelets and into one of said threaded openings, said fastener having a head portion engageable with a flange portion of the eyelet with which it is associated.

3. In combination, a metal base member having a side flange, a sheet of insulating material having a plurality of spaced openings, a metal eyelet in each opening having flange portions connected by a tubular portion that passes through a respective opening, a length of resistance Wire carried by said sheet of insulating material, said wire being Wound around said sheet of insulating material in at least one complete turn at points located between said eyelets and being wound partially around the tubular portions of said eyelets in half turns, at least a portion of said half turn being wedged between a flange portion of said eyelets and said sheet of insulating material, one of said eyelets being connected with the end of said length of said resistance wire, a plurality of threaded openings in said side flange aligned with said eyelets, an electrically conductive fastener having a shank portion passing through another of said eyelets and threaded into one of the threaded openings in said side flange, said fastener having a portion of larger diameter than said shank portion that engages a flange portion of the eyelet it is associated with, and a rivet passing through said one of said eyelets and engaging said side flange to electrically connect said one eyelet with said side flange and to mechanically support the sheet of insulating material from said side flange.

References Cited in the file of this patent UNITED STATES PATENTS 1,008,326 Grigsby Nov. 14, 1911 1,026,798 Gill May 21, 1912 1,957,227 Reimers et a1 May 1, 1934 2,021,509 Hastings Nov. 19, 1935' 2,314,793 Law Mar. 23, 1943 2,613,287 Geiger Oct. 7, 1952 2,726,304 Gribble Dec. 6, 1955 2,774,063 Grinstead et a1 Dec. 11, 1956 2,836,789 M-aly May 27, 1958 

1. IN COMBINATION, A METAL BASE FORMED WITH A SIDE FLANGE, SAID SIDE FLANGE HAVING A PLURALITY OF SPACED THREADED OPENINGS, A RESISTANCE ASSEMBLY SUPPORTED BY SAID SIDE FLANGE INCLUDING A SHEET OF INSULATING MATERIAL UPON WHICH IS WOUND A LENGTH OF RESISTANCE WIRE, A PLURALITY OF EYLETS LOCATED IN SPACED OPENINGS IN SAID INSULATING MATERIAL AND CONNECTED WITH SPACED POINTS OF SAID RESISTANCE WIRE, ONE OF SAID EYLETS BEING CONNECTED WITH THE END OF THE LENGTH OF SAID RESISTANCE WIRE, SAID EYELETS BEING LOCATED RESPECTIVELY IN ALIGNMENT WITH THE THREADED OPENINGS FORMED IN THE SIDE FLANGE, FIRST AND SECOND SHEETS OF INSULATING MATERIAL ONE OF WHICH IS POSITIONED BETWEEN SAID RESISTANCE ASSEMBLY AND SAID SIDE FLANGE AND THE OTHER OF WHICH IS POSITIONED ON THE OPPOSITE SIDE OF SAID RESISTANCE ASSEMBLY, AN ELECTRICALLY CONDUCTIVE RIVET PASSING THROUGH SAID ONE EYLET AND ENGAGING SAID SIDE FLANGE FOR ELECTRICALLY CONNECTING SAID ONE EYELET WITH SAID SIDE FLANGE AND FOR MECHANICALLY SUPPORTING SAID RESISTANCE ASSEMBLY AND SAID SHEETS OF INSULATING MATERIAL FROM SAID SIDE FLANGE, AND A SCREW ADAPTED TO BE PASSED THROUGH ANOTHER OF SAID EYLETS AND THREADED INTO ONE OF SAID THREADED OPENINGS FOR ELECTRICALLY CONNECTING ANOTHER OF SAID EYLETS WITH SAID SIDE FLANGE. 